Process control systems, like those used in chemical, petroleum or other processes, typically include one or more process controllers and input/output (I/O) devices communicatively coupled to at least one host or operator workstation and to one or more field devices or instruments via analog, digital or combined analog/digital buses. The field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure and flow rate sensors), perform process control functions within the process such as opening or closing valves and measuring process control parameters. The controllers receive signals indicative of process measurements made by the field devices, process this information to implement a control routine, and generate control signals that are sent over the buses or other communication lines to the field devices to control the operation of the process. In this manner, the controllers may execute and coordinate control strategies or routines using the field devices via the buses and/or other communication links communicatively coupling the field devices.
Information from the field devices and the controllers may be made available to one or more host applications (i.e., routines, programs, etc.) executed by the operator workstation (e.g., a processor-based system) to enable an operator and/or engineer to perform desired functions with respect to the process, such as viewing the current state of the process (e.g., via a graphical user interface), evaluating the process, modifying an operation of the process (e.g., via a visual object diagram), etc. In many instances, host applications achieve these ends by interacting with field devices based upon universal commands and functions implemented by each field device (e.g., reading the primary variable of the field device). However, field device manufacturers frequently develop device-specific commands and/or functionality that provides added value to the field device by enabling access to unique functions and/or data within the field device.
To enable host applications to interact with any number of different field devices, each having different device-specific functionality, manufacturers typically provide a file, which is associated with each field device they produce to be implemented via the host application, to describe and enable access to the unique functionality of the device. Such files are commonly known as Device Descriptions (DDs). In particular, DDs are often based on the Electronic Device Description Language (EDDL) and provide a structure and/or standardized format to describe and specify every accessible variable, command, function, procedure, menu, etc., associated with the corresponding field devices. Accordingly, process controllers and/or workstations may use DDs to facilitate interpretation, control, configuration, and/or management of field devices.